Method for preparing fluorocarbon dispersions

ABSTRACT

METHOD FOR PREPARING A FLUORINATED POLYMER DISPERSION IN A LUBRICATING COMPOSITION BY ADMIXING A FLUORINATED POLYMER, A HALOGENATED HYDROCARBON CONTAINING FLUORINE, A LUBRICATING OIL BASE AND A DISPERSANT ADDTIVE TO EFFECT A DISPERSION AND THEREAFTER REMOVING THE HALOGENATED HYDROCARBON.

United States Patent O 3,806,455 METHOD FOR PREPARING FLUOROCARBON DISPERSIONS William R. Siegart, Poughkeepsie, Ralph C. Suber, Wappingers Falls, N. and William D. Blackley, Lake Elmo, Minn., and James G. Dadura, Fishkill, N.Y., assignors to Texaco Inc., New York, N.Y. No Drawing. Filed Nov. 6, 1972, Ser. No. 304,176 Int. Cl. C10m 1/38 U.S. Cl. 252-463 9 Claims ABSTRACT OF THE DISCLOSURE Method for preparing a fluorinated polymer dispersion in a lubricating composition by admixing a fluorinated polymer, a halogenated hydrocarbon containing flue rine, a lubricating oil base and a dispersant additive to effect a dispersion and thereafter removing the halogenated hydrocarbon.

BACKGROUND OF THE INVENTION This invention is concerned with a lubricating oil composition and, more particularly, with a method for preparing a lubricating oil composition containing a fluorinated polypropylene or fluorinated polystyrene.

The search for improved lubricating oil compositions to meet increasingly severe thermal stability, corrosion inhibition and load-carrying specifications as well as meeting new environmental requirements is never ending. Certain classes of fluorinated polymers promise to be valuable in providing improved lubricating oil compositions. However, the fluorinated polymers in question are not directly soluble in lubricating base oils and could not be dispersed therein to produce an eflective lubricating oil composition.

A novel method has now been found for providing a lubricating oil composition containing a fluorinated polystyrene and a fluorinated polypropylene dispersed therein.

DESCRIPTION OF THE PRIOR ART U.S. 3,652,238 discloses an antistatic fuel composition containing a fluorinated polystyrene or fluorinated polypropylene.

U.S. 2,737,452; 3,666,656 and 3,272,744 disclose conventional lubricating oil dispersants.

SUMMARY OF THE INVENTION The method of the invention comprises the steps leading to the production of a solution or dispersion of a prescribed fluorinated polystyrene or fluorinated polypropylene in a mineral or a synthetic ester lubricating oil base.

In general, the novel process of the invention involves preparing a mixture of the prescribed fluorocarbon with a polyhalogenated methane or ethane which contains some fluorine, a lubricating oil base and a lubricating oil dispersant additive, agitating the mixture to effect dispersion of the fluorocarbon in the lubricating oil base and then removing the polyhalogenated methane or ethane.

More specifically, a fluorinated polystyrene represented by the formula: (C H F where x has a value from 3 to 5 and a fluorinated polypropylene represented by the formula: (C HF in which x has a value from 20 to 40, is dissolved in a polyhalogenated methane or ethane which contains fluorine among the halogens. A mineral or synthetic ester lubricating oil base together with a lubricating oil dispersant is added to the solution of the fluorinated polystyrene or fluorinated polypropylene. The mixture is agitated to effect solution or dispersion of the fluorinated polymer in the dispersant-containing lubricating oil base. The resultant solution is then treated to remove the prescribed polyhalogenated methane or 3,806,455 Patented Apr. 23, 1974 polyhalogenated ethane solvent from the solution leaving a lubricating oil composition containing a fluorinated polymer.

The order in which the components are mixed is not considered to be critical. All of the components can be mixed simultaneously and with agitation will produce a lubricating oil composition containing a fluorinated polymer dispersed therein. It is essential that the method be conducted employing a polyhalogenated methane or ethane which contains fluorine and a lubricating oil dispersant in order to elfect solution of the fluorinated polymer in the lubricating oil base. Convenience and ease of preparation dictate preparing a solution of the fluorinated polymer in a polyhalogenated methane or ethane containing fluorine and admixing this solution with a lubricating oil base containing a lubricating oil dispersant.

Not all fluorocarbons can be dissolved in a lubricating oil. Fluorinated petroleum wax could not be dissolved in a lubricating oil composition by this method. The amount of the prescribed fluorocarbon which can be dissolved in a mineral oil base is limited and is related to the concentration of the dispersant in the oil base. In general, the lubricating oil composition can contain from about 0:1 to 5 weight percent of the dispersant and the fluorocarbon will amount to about 1 to 10 weight percent of the dispersant.

The fluorinated polymers which can be employed in the present process are certain fluorinated polystyrene and fluorinated polypropylene. Fluorinated polystyrene has the empirical formula C H F where x is 3 to 5 and a method for preparing these compounds is disclosed in U.S. 3,380,983. According to this reference, a fluorinated polystyrene is prepared by contacting a polystyrene having a molecular weight between about 10,000 and 50,000 with gaseous fluorine in the presence of an alkali metal fluoride catalyst at a temperature between about 20 and 105 C. The resulting products have the empirical formula (C H F where x is 3 to 5 and have a melting point of to C.

A specific fluorinated styrene disclosed is represented by the empirical formula:

has a molecular weight of 2590 and a melting point of 8590 C. This fluorinated polystyrene comprises a mix ture of telomeric compounds of varying chain length having an average of 3.87 repeating units where each rcpeating C H F unit in the chain consists of two chemically fluorinated cyclohexane analogs of styrene.

Fluorinated polypropylene has the empirical formula:

( s sh in which x has a value from 20 to 40 and is prepared as described in U.S. 3,652,238.

Following the method of this invention, the prescribed fluorinated polymer can be dissolved in a mineral or a synthetic lubricating base oil which does not ordinarily dissolve the fluorinated polymer, i.e. the base oil is not a solvent for the fluorinated polymer. The mineral lubricating oil base can be a paraflinic or naphthenic or a mixture of both types of mineral oils. The mineral oil will generally be a refined paraflinic oil and will have an S.U.S. viscosity at F. ranging from about 50 to 1000. The preferred mineral base oils have an S.U.S. viscosity at 100 F. ranging from about 70 to 300. Synthetic lubricating oil bases, including ester base oils, polyalkylene oxide esters, silicones, fluorinated oils and per-fluorohydrocarbons, can also be employed in the present method.

Any conventional lubricating oil dispersant can be employed in the process of this invention. Etfective dispersants in this general class are the oil-soluble nitrogen-containing methacrylate co-polymers which are described in U.S. 2,737,452 and U.S. 3,666,656, the polyalkylene polyamine type dispersants as disclosed in U.S. 3,565,804, and the alkenylsuccinic acid or anhydride-alkylene polyamine reaction products as described in U.S. 3,131,150. The cited disclosures on dispersants are incorporated in the present application. An essential or critical feature of the instant process is the employment of a lubricating oil dispersant in order to effect and maintain a dispersion of the prescribed fluorinated polymer in the lubricating oil composition.

The polyhalogenated methane or ethane solvents employed in the present process are the fluorinated compounds conventionally known as Freon compounds. Effective polyhalogenated methanes include fiuorotrichloromethane, dichlorodifluoromethane dichlorofluoromethane, chlorodifluoromethane, tetrafluoromethane and chlorotrifluoromethane. Efiective polyhalogenated ethanes include trichlorotrifluoroethane, dichlorotetrafluoroethane, chloropentafiuoroethane and tetrachlorodifluoroethane. Some of these materials are gaseous under ordinary conditions and must be cooled and used under pressure when employed in this process. Compounds not containing fluorine are not effective in this process.

The concentration of the polyhalogenated methane or ethane in the process is not critical. It is employed in a sufiicient amount to dissolve the fluorinated polymer and maintain it in solution until the fluorinated polymer has been dispersed in the lubricating oil. In general, it will be found convenient to employ the polyhalogenated methane or ethane solvent in an amount ranging from about 2 to 20 volume percent based on the lubricating oil base. The polyhalogenated methane or ethane is thereafter separated from the lubricating oil composition by suitable known means, such as distillation.

The following examples illustrate the practice of this invention:

Example I 0.2 grams of fluorinated polystyrene having the formula:

was mixed with 5 cc. of trichlorotrifluoroethane. A second mixture of 25 cc. of a paraffinic mineral oil having an S.U.S. viscosity at 100 F. of about 140 and 5 cc. of a nitrogen-containing dispersant from polyisobutenyl-llOO- succinic anhydride and tetraethylene-pentamine was prepared. The two solutions were mixed and agitated to form a uniform mixture. The resulting mixture was placed on i a boiling water bath to remove the trichlorotrifiuoroethane A mineral lubricating oil composition containing fluorinated polystyrene was prepared and tested for its rust inhibiting properties in the Ford Rust Test. This test is run in a 1964 Ford-289 V-8 engine modified by enlarging the compression ring gaps to 0.039 inches, replacing the oil filter with a cover plate and jacketing of the oil pan and rocker arm covers to allow cooling water to be circulated in contact with the pan and covers.

The crankcase oil is tested by running the engine for 45 hours under a load of 28: brake horsepower, at a speed of 1500:10 r.p.m., an oil pressure of 30:5 p.s.i. with a jacket outlet temperature of 90:3 R, an oil gallery temperature of 110:2 F., and intake air temperature of i4 F., While circulating 60 F. water through the jacketed covers.

The base blend-consisted of mineral lubricating oil having an S.U.S. viscosity at 100 F. of about 3739 and contained about 3.7 percent of a polybutene-l 100-succinic anhydride-tetraethylenepentamine reaction product, about 1.1 percent of a copolymer of butyl and stearyl methacrylates, about 1.35 percent of a zinc dialkyldithiophosphate (0.15 percent Zn) about 1.5 percent calcium overbased calcium sulfonate (0.18 percent Ca) and about p.p.m. silicone antifoamant.

The lubricating oil being treated consisted of the base blend and 0.5 weight percent of fluorinated polystyrene having the formula:

In the Ford Rust Test, the internal and external portions of the valve lifters are rated on the basis of 1 to 10', with the rating of 10 being for a perfectly clean valve lifter, and an average rating for the external and internal portions determined. The test results are given in the table below.

TABLE L-FORD RUST TEST Valve litter rating (10clean) Run Oil External Internal Average 1 Base blend 6.0 3. 5 4. 8 2. Base blend plus 0.5 wt. percent; 7.5 6.0 6.8

fluorinated polystyrene.

where x has a value from 3 to 5 and fluorinated polypropylene having the formula:

where x has a value from 20 to 40 which comprises admixing a lubricating oil base with from about 0.1 to 5 weight percent of a lubricating oil dispersant, from 1 to 10 Weight percent based on said dispersant of said fluorinated polymer and a polyhalogenated methane or ethane containing fluorine among the halogens, agitating the mixture to effect solution of said fluorinated polystyrene or polypropylene in said lubricating oil base and removing said polyhalogenated methane or ethane.

2. A method according to claim 1 in which said lubricating oil base is derived from a mineral oil.

3. A method according to claim 1 in which said lubricating oil base is a parafiinic oil having an S.U.S. viscosity at 100 F. ranging from about 50 to 1000.

4. A method according to claim 1 in which said lubricating oil dispersant is selected from the class consisting of nitrogen-containing methacrylate copolymers, polyal-kylene polyamines, hydrocarbyl thiophosphonates and alkenylsuccinic acid or anhydride-alkylene polyamine reaction products.

5. A method according to claim 1 in which said dispersant is the reaction product of polyisobutylene-llOO- succinic anhydride and tetraethylene-pentamine.

6. A method according to claim 1 in which said polyhalogenated ethane contains chlorine and fluorine.

7. A method according to claim 1 in which said polyhalogenated ethane is trichlorotrifluoroethane.

8. A method according to claim 1 in which said polyhalogenated ethane is dichlorotetrafluoroethanc.

9. A method according to claim 1 in which said polyhalogenated ethane is chloropentafluoroethane.

References Cited UNITED STATES PATENTS 5 Catlin et a1. 44-62 Stuart et a1. 252-34.7 Schullenberg et a1. 262--32.7 E Siegart et a1. 260-93.5A Honnen et a1. 252-50 10 6 Honnen et a1. 252-50 Bialy et a1. 44-62 Stanley 252S 1.5 A Foucher et a1. 252-46.7

US. Cl. X.R. 

